U.S. patent number 5,002,457 [Application Number 07/486,814] was granted by the patent office on 1991-03-26 for apparatus for storing stacks of articles and subsequently unstacking the articles and feeding the articles to working equipment.
This patent grant is currently assigned to Dorner Mfg. Corp.. Invention is credited to Wolfgang C. Dorner, Todd A. Eggebrecht, Kenneth N. Hansen, John C. Redding.
United States Patent |
5,002,457 |
Dorner , et al. |
March 26, 1991 |
**Please see images for:
( Certificate of Correction ) ** |
Apparatus for storing stacks of articles and subsequently
unstacking the articles and feeding the articles to working
equipment
Abstract
An apparatus for stacking and storing articles and subsequently
unstacking the articles. The apparatus includes a first conveyor to
convey a plurality of articles, and a plurality of secondary
conveyors are disposed normal to a side edge of the first conveyor.
To store the articles, each article is stopped on the conveyor and
is pushed laterally from the main conveyor into bearing engagement
against a movable stop member on a secondary conveyor. Additional
articles are pushed onto the secondary conveyor into engagement
with the preceding article to form a composite stack. The composite
stack can be lifted from the secondary conveyor by a lifting
mechanism to a storage site, and subsequently, when it is desired
to release the stack from storage, the stack is lowered back onto
the secondary conveyor. As the composite stack approaches the
downstream end of the secondary conveyor, the individual articles
are separated from the stack and fed to a third conveyor, which
conveys the articles in uniformly spaced relation to working
equipment.
Inventors: |
Dorner; Wolfgang C.
(Oconomowoc, WI), Hansen; Kenneth N. (Waukesha, WI),
Eggebrecht; Todd A. (Waukesha, WI), Redding; John C.
(Oostburg, WI) |
Assignee: |
Dorner Mfg. Corp. (Hartland,
WI)
|
Family
ID: |
26933646 |
Appl.
No.: |
07/486,814 |
Filed: |
March 1, 1990 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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240717 |
Sep 6, 1988 |
4951803 |
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Current U.S.
Class: |
414/790.3;
198/359; 198/370.1; 414/798.6; 414/798.7; 414/798.9; 74/520 |
Current CPC
Class: |
B65G
47/5113 (20130101); Y10T 74/20588 (20150115) |
Current International
Class: |
B65G
47/51 (20060101); B65G 057/00 () |
Field of
Search: |
;414/789,790.3,797.2,798.6,798.7,798.9 ;74/520
;198/359,370,372,534 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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960177 |
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Dec 1974 |
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CA |
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61-257806 |
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Nov 1986 |
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JP |
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Primary Examiner: Olszewski; Robert P.
Assistant Examiner: Milef; Boris
Attorney, Agent or Firm: Andrus, Sceales, Starke &
Sawall
Parent Case Text
This is a division of application Ser. No. 07/240,717, filed Sept.
6, 1988 now U.S. Pat. No. 4,951,803.
Claims
I claim:
1. In combination, conveyor means to convey a plurality of articles
in a downstream direction, stop means mounted for movement with
respect to said conveyor means from a non-obstructing position
where said stop means will not interfere with movement of said
articles on said conveyor means to an obstructing position where
said stop means is disposed in the path of movement of said
articles on said conveyor means, said stop means also being mounted
for movement longitudinally of said conveyor means from a
downstream position to an upstream position, said stop means being
freely movable in a downstream direction, first operating means for
moving said stop means between the obstructing and non-obstructing
positions, second operating means for moving said stop means from
the downstream to the upstream position, a first of said articles
on said conveyor engaging said stop means when in said obstructing
and upstream position, and each subsequent article engaging the
preceding article to form a train of articles on said conveyor
means, pusher means disposed at the downstream end of said conveyor
means and mounted for movement between a storage position where
said pusher means will not interfere with discharge of said
articles from said conveyor means and an extended position where
said pusher means is located above said conveyor means and upstream
of the downstream position of said stop means, and third operating
means for moving said pusher means from the storage position to the
extended position to push any articles remaining on said conveyor
means to a location upstream of the downstream position of said
stop means, whereby said stop means can then move said remaining
articles to the upstream end of said conveyor means.
2. The apparatus of claim 1, wherein said stop means is mounted for
pivotal movement between said obstructing and non-obstructing
positions, said non-obstructing position being at a level beneath
said conveyor means.
3. In an apparatus for unstacking articles, conveyor means to
convey a group of articles in a downstream direction, separating
means disposed at the downstream end of said conveyor means for
separating each article from said group, stop means mounted for
movement with respect to said conveyor means from a non-obstructing
position where said stop means will not interfere with movement of
said articles on said conveyor means to an obstructing position
where stop means is disposed in the path of movement of said
articles on said conveyor means, said stop means also being mounted
for movement longitudinally of said conveyor means from a
downstream position to an upstream position, first operating means
for moving said stop means between the obstructing and
non-obstructing positions, second operating means for moving said
stop means between the downstream and upstream positions, pusher
means disposed at the downstream end of said conveyor means and
mounted for movement between a storage position where said pusher
means will not interfere with separation of said articles from said
group and an extended position where said pusher means is located
above said conveyor means and upstream of the downstream position
of said stop means, and third operating means for moving said
pusher means from the storage position to the extended position to
push said group of articles to a location upstream of the
downstream position of said stop means, subsequent operation of
said first and second operating means acting to move said group to
the upstream end of said conveyor means.
4. The apparatus of claim 3, wherein said stop means is freely
movable in a downstream direction with respect to the conveyor
means.
5. The apparatus of claim 4, wherein said stop means is mounted for
pivotal movement between said non-obstructing and obstructing
positions about an axis tranverse to the direction of movement of
said conveyor means, and said apparatus includes means to prevent
pivotal movement of said stop means from the obstructing position
to the nonobstructing position by pressure of said objects against
said stop means.
6. The apparatus of claim 5, wherein said means to prevent pivotal
movement comprises a toggle linkage having a locked position when
said stop means is in the obstructing position and having an
unlocked position when said stop means is in the unobstructing
position, first operating means having means being operably
connected to said toggle linkage to move said linkage from said
locked to the unlocked position.
7. The apparatus of claim 3, wherein said separating means includes
an end member spaced from the downstream end of said conveyor means
to provide a gap, said articles individually being discharged
through said gap.
8. The apparatus of claim 7, wherein said end member is provided
with an opening and said pusher means comprises a plate disposed
within the opening when said pusher means is in the storage
position.
Description
BACKGROUND OF THE INVENTION
Automatic conveyor systems are used to convey small parts or
articles to working equipment where working operations are
performed on the parts. In certain types of conveyor systems, the
articles are stacked in side-by-side relation and the articles are
individually separated from the stack and fed in uniform spaced
relation to downstream working equipment.
If the system is not fully coordinated, due to upstream equipment
operating at a faster rate than the downstream working equipment,
or if a stoppage occurs in the downstream working equipment, it is
desirable to store the articles. Subsequently, the articles can be
discharged from the storage unit and fed to the downstream working
equipment at a uniform rate.
SUMMARY OF THE INVENTION
The invention is directed to a method and apparatus for stacking
and storing stacks of articles and subsequently separating the
individual articles from the stack and feeding the articles to
working equipment. The apparatus includes a main conveyor to convey
a plurality of small parts or articles, such as video cassette
containers, jewelry boxes, or the like. Under normal operating
conditions, individual parts or stacks of parts are conveyed on the
main conveyor to downstream working equipment. However, in the
event of a stoppage in the downstream working equipment, or if the
production rate of upstream equipment exceeds that of downstream
equipment, the partsd or stacks are routed via a by-pass conveyor
to a storage unit.
The storage unit includes a plurality of secondary conveyors that
are disposed normal to a side edge of the by-pass conveyor. As each
part stack is conveyed along the by-pass conveyor, it is stopped at
a position aligned with a secondary conveyor and the part or stack
is then pushed laterally by a pushing mechanism onto the secondary
conveyor and into bearing engagement with a movable stop member.
Succeeding parts or stacks are pushed from the by-pass conveyor
onto the secondary conveyor and into engagement with the preceding
part or stack to form a composite stack.
When a composite stack of predetermined size has been formed, the
composite stack is lifted upwardly from the secondary conveyor by a
lift mechanism to a storage site. Subsequently, when the downstream
stop-page has been corrected and it is desired to feed the articles
to downstream working equipment, the composite stack is lowered
back onto the moving secondary conveyor and the stop member is
lowered to a non-obstructing position. As the composite stack
approaches the downstream end of the secondary conveyor, each
article is separated from the composite stack and fed to the main
conveyor, located on the opposite side of the storage unit from the
by-pass conveyor, where the articles are individually conveyed to
downstream working equipment.
In a preferred form of the invention, the storage unit includes a
pair of individually movable storage sections or magazines, each
having a plurality of side-by-side storage compartments and a
secondary conveyor is associated with each compartment. The parts
or stacks are sequentially fed from the by-pass conveyor onto the
secondary conveyors of the compartments of one of the magazines,
and then fed onto the secondary conveyors of the compartments of
the second of the magazines. While the parts are being fed to the
second magazine, the first magazine is elevated to lift the tier of
composite stacks from the secondary conveyors and index the first
magazine to receive a second tier of additional stacks from the
main conveyor.
When unloading the composite stacks from the storage unit, the
procedure is reversed with the second magazine being lowered to
sequentially deposit the stacks from each compartment onto the
respective secondary conveyors, followed by lowering of the first
magazine to release the stacks onto the respective secondary
conveyors. While the stacks are being released from the
compartments of the first magazine, the second magazine is indexed
downwardly to a position to release a second tier of stacks from
the compartments of the second magazine.
With the invention, if the rate of delivery of individual parts or
stacks is greater than the rate at which the parts can be accepted
by downstream working equipment, the parts can be stored in the
storage unit and subsequently released to the working equipment to
provide a uniform rate of flow of parts to the working equipment at
all times.
Other objects and advantages will appear in the course of the
following description.
DESCRIPTION OF THE DRAWINGS
The drawings illustrate the best mode presently contemplated of
carrying out the invention.
In the drawings:
FIG. 1 is a top plan view of the apparatus of the invention with
parts broken away;
FIG. 2 is a view taken along line 2--2 of FIG. 1;
FIG. 3 is a section taken along line 3--3 of FIG. 2;
FIG. 4 is an enlarged fragmentary front elevation showing the
pivoting stop member and the discharge chutes;
FIG. 5 is a fragmentary horizontal section showing the discharge
end of one of the secondary conveyors in the storage unit;
FIG. 6 is an enlarged section showing the separation of the
articles from a stack and the feeding of the separated articles to
the discharge conveyor.
FIG. 7 is a view similar to FIG. 6 and showing the pusher in an
extended position over the secondary conveyor; and
FIG. 8 is a view taken along line 8--8 of FIG. 7.
DESCRIPTION OF THE ILLUSTRATED EMBODIMENT
As shown in FIG. 1 and 2, the apparatus includes a main frame or
supporting structure 1, that supports a main or conveyor 42. In
normal operation of the conveyor system, the individual parts or
articles 3 are conveyed directly on conveyor 42 to downstream
working equipment. In the event the downstream working equipment
cannot handle the parts at the rate they are being delivered on
conveyor 42, the parts are routed to a by-pass conveyor 2 and then
stored or accumulated in a storage unit, and subsequently released
at a uniform rate to conveyor 42 and delivered to working
equipment. To accelerate the storage operation, the parts or
articles 4 can be initially stacked in side-by-side stacks 3 by
stacking equipment, not shown, and the stacks 3 are delivered in
spaced relation on conveyor 2 to the storage unit. Stacking is not
essential, and if the production rate is slow, the individual parts
4 can be fed on conveyor 2 directly to the storage unit.
Conveyor 2 is of conventional construction and includes a generally
U-shaped frame 5 which supports a belt 6 for endless travel. Belt 6
is supported on a drive pulley or spindle and an idler pulley, not
shown, and the drive pulley is driven in a conventional manner to
move the belt 6 in its endless path.
To effect storage of the stacks 3, a plurality of pairs of stop
assemblies 7 are located in spaced relation along coneyor 2 and
each stop assembly, as will be hereinafter described. includes a
gate which is movable between an obstructing position where it is
located above belt 6 in the path of travel of stack 3, to stop the
stack, to a retracted or non-obstructing position, where it will
not interfere with movement of the stacks on conveyor 2.
A pusher unit 8 is associated with each stop assembly 7. With a
stack 3 stopped on conveyor 2 by stop assembly 7, pusher unit 8 is
actuated to push the stack laterally from conveyor 2 onto one of a
plurality of parallel secondary conveyors 13, which extend
laterally from a side edge of conveyor 2.
Each secondary conveyor unit 13 is composed of a generally U-shaped
frame 15 which is supported at its respective ends on horizontal
beams 16 and 17 which are connected to main frame 1. Each conveyor
13 includes a belt 18 which is trained about a drive pulley 20 and
an idler pulley 19. As shown in FIG. 1, common shaft 21 is
connected to the drive pulleys 20 of all of the conveyors 13 and
shaft 21 is driven by a motor 22 operating through a gear box 23.
The manner of driving the parallel conveyors 13 is similar to that
described in U.S. Pat. No. 3,923,148.
Associated with each conveyor 13 is a pair of movable stop members
24 which straddle the conveyor.
As best illustrated in FIG. 4, the length of the articles 4 in
stack 3 is greater than the distance between the side edges of
conveyor 13, so that the ends of the stack project outwardly beyond
the respective conveyors 13.
As best shown in FIGS. 5 and 6, the lower ends of stop members 24
are each connected to an arm 25 that extends along the respective
side edges of conveyor 13 and the upstream ends of arms 25 are
pivotally connected to a shaft 26 that extends transversely beneath
the conveyor. The ends of shaft 26 are supported by upstanding
posts 27 that extend upwardly from plate 28. As shown in FIG. 6,
plate 28 is mounted on the carrier 29 of a rodless cylinder 30 and
the cylinder is supported on the fixed horizontal frame member
31.
Stops 24 are adapted to be moved between an upper obstructing
position, as shown in FIG. 2, where they will be engaged by the
side portions of the forward end of the stack 3 to stop movement of
the stack on the moving conveyor 13, to a lower non-obstructing
position, as illustrated in FIG. 6. To move the stops 24 between
the positions, one end of a pneumatic cylinder 32 is pivotably
mounted through lugs 33 to plate 28 and a piston rod 34 extends
outwardly from the opposite end of cylinder 32 and is connected to
a block 35 that is mounted on transverse shaft 36. Rollers 37,
which are journalled on the shaft 36 and straddle block 35, ride on
plate 28 as the piston rod 34 is extended and retracted.
As shown in FIG. 4, a plate 38 is also mounted for pivotal movement
on shaft 36 and the lower edge of plate 38 is provided with
suitable cut-outs to receive block 35 and rollers 37. The upper end
of plate 38 is pivotally connected by shaft 39 to arms 25 of stops
24.
With this arrangement, extension of piston rod 34 will move shaft
36 in an upstream direction, thereby pivoting plate 38 downwardly
and correspondingly pivoting stops 24 to the lower non-obstructing
position, as shown in FIG. 6, where they will not interfere with
movement of stack 3 on conveyor 13.
The rodless cylinder 30 is of conventional construction and
includes a piston which is connected to carrier 29. Introducing
fluid into the outer end of cylinder 30 will move the piston and
carrier 29 and stop members 24 toward the main conveyor 2. As the
stacks 3 are pushed onto the conveyors 13, the leading end of the
stack will engage stops 24 to move the stops and carrier 29
relative to cylinder 30. In this condition, the pressure in the
cylinder 30 is released so that only the friction of the piston
operating within the cylinder will resist the movement of the stack
3 as it is pushed onto the secondary conveyors.
As each succeeding stack is pushed onto the secondary conveyor, it
will engage the trailing edge cf the preceding stack and again push
stops 24 in a direction away from conveyor 2. This operation of
feeding stacks from conveyor 2 to each secondary conveyor 13 is
continued until carrier 29 reaches the end of its stroke and a
composite stack 40 of desired length has been formed on the
secondary conveyor. When stops 24 are in the upright obstructing
position, the links 25 and 38 act as a toggle mechanism in which
the pivot axis 39 is positioned upstream or overcenter of a
vertical plane passing through the pivot axis 36. In an overcenter
or on-center condition, the toggle linkage is in a locked condition
and the pressure of stack 3 against stops 24 will not pivot the
stops downwardly. Thus, the stops 24 are locked in the upright
position and extension of piston rod 34 will release the toggle
linkage and lower the stops.
If it is desired to feed the articles 4 from the composite stack 40
to working equipment, the stops 24 are moved to the lower release
position, as shown in FIG. 6, and the composite stack will then
move toward the downstream end of the secondary conveyor on the
moving conveyor belt 18. As the composite stack 40 reaches the
downstream end of the secondary conveyor, each article 4 will be
separated from the composite stack, as shown in FIG. 6, and will be
discharged down a curved chute 41 to a discharge conveyor 42.
Conveyor 42 can have a construction similar to that of conveyor 2
and acts to convey each individual article in substantially
uniformly spaced relation to working equipment.
In the event there is a stoppage downstream, or in the event the
downstream working equipment cannot operate at a speed sufficient
to handle the rate of feed of articles 4 on in-feed conveyor 2 from
the secondary conveyors 13, a storage system is incorporated with
the secondary conveyors.
Storage unit 43, as best shown in FIG. 3, is composed of pair of
sections 44 and 45 and, as illustrated, three secondary conveyor
units 13 are associated with each section 44, 45. However, the
storage unit can have any number of storage sections with one or
more secondary conveyors associated with each section.
Each storage section 44, 45 can be similar in construction to that
disclosed in U.S. Pat. No. 4,609,091 and includes a carriage or
magazine 44a, 45a which is adapted to be moved vertically on frame
1, by a drive mechanism that can be of the type shown in U.S. Pat.
No. 4,609,091. The construction of that patent is incorporated
herein by reference.
The movable magazine 44a of storage section 44 includes of a
plurality of spaced vertical plates 46 and the respective ends of
plates 46 are guided in vertical movement in guides 47 which are
mounted on beams 16 and 17 respectively. The sides of each plate 46
are provided with a plurality of vertically spaced angle-shaped
rails or supports 48, which define shelves to support the side
edges of the respective composite stacks 40 as will hereinafter be
described.
As illustrated in FIG. 3, magazine 44a defines three side-by-side
storage compartments, 50, 51 and 52 and the shelves 48 in the
storage compartment 51 are at a slightly higher level than the
shelves of storage compartment 50, in the range of about 1/2 inch.
Similarly, the shelves 48 of storage compartment 52 are at a
slightly higher elevation than the corresponding shelves of
compartment 51.
The magazine 45a is similar in structure to magazine 44a and
includes a plurality of spaced vertical plates 53, the ends of
which are guided for vertical movement in end guides 54, which are
mounted on the beams 16 and 17, respectively. A series of
vertically spaced angle-shaped rails 55 are mounted on each of the
plates 53 and serve to support the opposite sides of the composite
stack 40, as it is raised above the secondary conveyor 13, as will
be hereinafter described.
As shown in FIG. 3, magazine 45a defines three storage compartments
56, 57 and 58, and the rails 55 of storage compartment 57 are
located slightly above the corresponding rails of storage
compartment 56. Similarly, the shelves or rails 55 of storage
compartment 58 are located slightly above the corresponding rails
of storage compartment 57.
While the drawings show plates 46 and 53 extending continuously
along the length of conveyors 13, in some installations where
greater access is desired, the rails 48 and 55 can be supported by
spaced vertical strips instead of plates 46 and 53.
Each stop assembly 7, as best illustrated in FIG. 2, includes a
pivotable gate 60 that extends transversely across conveyor 2 and
the upper edge of gate 60 is pivoted to the lower ends of arms 61
that extend downardly from beam 62. Each gate 60 can be pivoted
from a generally vertical position where it will obstruct flow of
stacks 3 on conveyor 2 to an upper inclined position where it will
not interfere with flow of the stacks 3 on conveyor 2. To
individually pivot the gates 60, the piston rod 63 of a pneumatic
cylinder 64 is pivotally connected to an ear 65 that extends
outwardly from gate 60, while the cylinder 64 is pivoted to web 66
that extends upwardly from beam 62. By retracting piston rod 63,
gate 60 will be moved from the vertical obstructing position to the
upper non-obstructing position.
The pusher unit 8 that acts to push a stack 3 stopped by gate 60 on
conveyor 2 onto the corresponding conveyor 13, includes a pusher
plate 67 that is positioned alongside a side edge of conveyor 2.
Plate 67 is connected through bracket 68 to the carrier 69 of a
rodless cylinder 70 that is mounted by brackets 71 from beam 62.
Operation of cylinder 70 will move pusher plate 67 across conveyor
2 to push a stack 3 onto the corresponding conveyor 13.
Each chute 41 includes a pair of spaced curved guides 72 and a pair
of side plates 73. The lower end of the chute is spaced above the
belt of main conveyor 42, a distance slightly greater than the
thickness of article 4, so that an article 4 moving down chute 41
will not engage the side of a previously discharged article on
conveyor 42 if that article has not been fully conveyed away on
conveyor 42 by the time the succeeding article approaches the
conveyor.
Under high speed operating conditions articles 4 being fed down
chute 41 may slightly overlap each other to provide a shingled
effect. To eliminate the shingled condition, a bar 74 can be
mounted slightly above conveyor 42 at a location slightly
downstream of each conveyor 13 in position to be engaged by the
upper or shingled article. The leading end of the shingled article
will engage bar 74 to hold back its movement until it can fall onto
the conveyor 42 behind the lower of the shingled articles.
To aid in transferring articles 4 from each secondary conveyor 13
to the main conveyor 42, a vertical plate 75 is mounted in a
location spaced from the end of each conveyor 13 and the ends of
the plate 75 are attached between parallel plates 76. As the
article 4 tilts as it falls from the downstream end of conveyor 13,
the upper edge of the article will engage plate 75, as shown in
FIG. 6, to guide the article to chute 41.
In certain instances, depending on the programming of the conveyor
system, the operation of a conveyor 13 may be terminated before all
of the articles have been transferred to the chute 41 and conveyor
42. In this case it is desirable that the remaining articles on
conveyor 13 be moved upstream to a location adjacent the in-feed
conveyor 2 in position for a subsequent storing operation. In this
connection, each plate 75 is formed with a central opening 77 and a
pusher 78 is mounted within the opening 77. During normal
operation, pusher 78 is flush with the face of plate 75 that faces
conveyor 13, as shown in FIG. 6. However, if the transfer of
articles 4 is stopped before all the articles have been transferred
to the chute 41, the remaining articles are pushed upstream to a
location within the stroke of stop members 24 so that the stop
members can then return the remaining articles to the upstream end
of conveyor 13.
To actuate pusher 78, the piston rod 79 of a fluid cylinder 80 is
attached to a bracket 81 mounted on the rear face of pusher 78. By
extending piston rod 79, pusher 78 will be moved upstream with
respect to conveyor 13 to push the group of remaining articles to a
location where they can be engaged by the stop members 24 when the
stop members are pivoted to their upper operative position.
Pusher 78 is guided in movement by a guideway 82 that extends
rearwardly from the pusher and is slidable on a T-shaped guide bar
83. Guide bar 83 is supported by spacer bars 84, 85 from plates 76.
The forward stroke of pusher 78 is limited by engagement cf stop 86
on guideway 82 with bar 84.
In operation, stacks 3 are conveyed on conveyor 2 in spaced
relation. To store the stacks 3, the gate 60 of stop assembly 7
located immediately downstream of the conveyor 13 associated with
compartment 58 of carring 45a, is lowered to stop the stack on the
moving conveyor 2.
Pusher plate 67 is then actuated to push the stack 3 from conveyor
2 onto the conveyor 13 and into engagement with the movable stops
24. Stops 24 will move away from conveyor 2 as the stack is moved
onto the conveyor 13. As previously described, the toggle linkage
will prevent the stops 24 from pivoting downwardly as the stack 3
engages the stops.
A second stack is then stopped by the lowered gate 60 and the
second stack is then pushed onto the conveyor 13 associated with
compartment 58 and into engagement with the trailing end of the
first stack to form a composite stack 40. Again, stops 24 are
pushed downstream as the second stack is pushed onto the secondary
conveyor 13. This operation is repeated to form a composite stack
40 of desired length.
If at this stage, the blockage downstream has been corrected, the
composite stack 40 can be released from the conveyor 13 by pivoting
the stops 24 downwardly to the release position through operation
of cylinder 32, in which case each article 4 will be separated from
the composite stack and fed through chute 41 to the main conveyor
42, as shown in FIG. 6.
On the other hand, if it is desired to store the composite stack
40, the magazine 45a is indexed upwardly, bringing the shelves 55
of compartment 58 into engagement with the overhanging ends of the
composite stack to lift the composite stack upwardly from the
conveyor 13. The upward movement is only sufficient to raise the
stack in compartment 58 above the conveyor 13, but the shelves 55
of the adjacent compartment 57 will still be beneath the level of
the associated conveyor 13. This action is repeated with a second
composite stack 40 being similarly formed in compartments 57 and 56
and lifted from the respective secondary conveyors 13 by elevation
of the magazine 45a. When compartment 58, 57 and 56 have been
loaded with a first tier of composite stacks, the loading is
shifted to compartments 52, 51 and 50 of magazine 44a. As composite
stacks are formed in sequence i compartments 52, 51 and 50,
magazine 45a is elevated a distance approximately the height of a
stack to position the shelves 55 of compartment 58 in a ready
position so that the compartment 58 can be loaded with a second
tier stack when the loading of compartment 50 is completed. In this
manner, the storage compartments 58-56 of magazine 45a, as well as
storage compartments 52-50 of magazine 44a can be filled with the
stacked articles.
When it is desired to feed the stored stacks 40 to working
equipment, magazine 44a is lowered to return the lowermost stack 40
of compartment 50 onto the respective conveyor 13. At this time,
the lowermost stacks in the storage compartments 51 and 52 will be
above the level of the conveyor belts 18 of the respective
conveyors 13, so they will not contact the moving conveyor belts.
The stop members 24 associated with the conveyor 13 of storage
compartment 50 is then moved to the lowered or released position,
enabling the composite stack 40 from compartment 50 to move to the
downstream end of the secondary conveyor 13, where the articles 4
are individually separated from the stack and fed through the chute
41 to the conveyor 42.
After the lowermost stack 40 from storage compartment 50 has been
discharged from the conveyor 13, magazine 44a is again lowered in
an increment sufficient to position the lowermost stack in
compartment 51 on the moving belt 18 of the respective secondary
conveyor 13. At this time, the lowermost stack 40 in storage
compartment 52, is located at a level above the belts 18, so it
will not ride against the moving belt as the stack in compartment
51 is discharged by release of stop members 24.
In the same manner, the lowermost stack 40 is discharged from the
compartment 52 and subsequently the lowermost stacks are discharged
from storage compartments 56-58 by incremental lowering of magazine
45a. This procedure is repeated to release all of the stacks 40 in
compartments 50-52 and 56-58 onto the secondary conveyors 13.
As the shelves 48 and 55 are all at different levels, only the
stack 40 of a single storage compartment will ride on its
associated conveyor belt 18 and the stacks in the remaining storage
compartments will be spaced above the moving belts to prevent wear
or abrasion on the articles in the stack.
The independent operation of magazines 44a and 45a is important in
high speed applications for each magazine is only required to move
a short vertical distance during loading of the compartments of
that magazine, and the greater increment of vertical movement is
carried out during the period when the other magazine is being
loaded. This substantially increases the overall speed of operation
and enables the stacks to be loaded without interruption. At low
speed operation, the magazines could store different articles or
parts.
By virtue of the invention, stacks of side-by-side stacked articles
can be unstacked and fed at a uniform rate to working equipment. In
the event the working or downstream equipment cannot keep up with
the rate of unstacking, the stacks can be stored and subsequently
released at the desired time to provide the uniform feed rate to
the working equipment.
While the above description has shown the invention used to store
stacks of articles, it is contemplated that the invention can also
be employed to store individual objects or articles of various
configurations.
Various modes of carrying out the invention are contemplated as
being within the scope of the following claims particularly
pointing out and distinctly claiming the subject matter which is
regarded as the invention.
* * * * *